1 files changed, 121 insertions, 0 deletions
diff --git a/spec/ruby/core/kernel/caller_spec.rb b/spec/ruby/core/kernel/caller_spec.rb
new file mode 100644
index 0000000000..225f6fc458
--- /dev/null
+++ b/spec/ruby/core/kernel/caller_spec.rb
@@ -0,0 +1,121 @@
+require_relative '../../spec_helper'
+require_relative 'fixtures/caller'
+
+describe 'Kernel#caller' do
+  it 'is a private method' do
+    Kernel.private_instance_methods(false).should.include?(:caller)
+  end
+
+  it 'returns an Array of caller locations' do
+    KernelSpecs::CallerTest.locations.should_not.empty?
+  end
+
+  it 'returns an Array of caller locations using a custom offset' do
+    locations = KernelSpecs::CallerTest.locations(2)
+
+    locations[0].should =~ %r{runner/mspec.rb}
+  end
+
+  it 'returns an Array of caller locations using a custom limit' do
+    locations = KernelSpecs::CallerTest.locations(1, 1)
+
+    locations.length.should == 1
+  end
+
+  it 'returns an Array of caller locations using a range' do
+    locations = KernelSpecs::CallerTest.locations(1..1)
+
+    locations.length.should == 1
+  end
+
+  it 'returns the locations as String instances' do
+    locations = KernelSpecs::CallerTest.locations
+    line      = __LINE__ - 1
+
+    locations[0].should.include?("#{__FILE__}:#{line}:in")
+  end
+
+  it "returns an Array with the block given to #at_exit at the base of the stack" do
+    path = fixture(__FILE__, "caller_at_exit.rb")
+    lines = ruby_exe(path).lines
+    lines.size.should == 2
+    lines[0].should =~ /\A#{path}:6:in [`'](?:Object#)?foo'\n\z/
+    lines[1].should =~ /\A#{path}:2:in [`']block in <main>'\n\z/
+  end
+
+  it "can be called with a range" do
+    locations1 = caller(0)
+    locations2 = caller(2..4)
+    locations1[2..4].should == locations2
+  end
+
+  it "works with endless ranges" do
+    locations1 = KernelSpecs::CallerTest.locations(0)
+    locations2 = KernelSpecs::CallerTest.locations(eval("(2..)"))
+    locations2.should == locations1[2..-1]
+  end
+
+  it "works with beginless ranges" do
+    locations1 = KernelSpecs::CallerTest.locations(0)
+    locations2 = KernelSpecs::CallerTest.locations((..5))
+    locations2[eval("(2..)")].should == locations1[(..5)][eval("(2..)")]
+  end
+
+  it "can be called with a range whose end is negative" do
+    locations1 = caller(0)
+    locations2 = caller(2..-1)
+    locations3 = caller(2..-2)
+    locations1[2..-1].should == locations2
+    locations1[2..-2].should == locations3
+  end
+
+  it "must return nil if omitting more locations than available" do
+    caller(100).should == nil
+    caller(100..-1).should == nil
+  end
+
+  it "must return [] if omitting exactly the number of locations available" do
+    omit = caller(0).length
+    caller(omit).should == []
+  end
+
+  it "must return the same locations when called with 1..-1 and when called with no arguments" do
+    caller.should == caller(1..-1)
+  end
+
+  guard -> { Kernel.instance_method(:tap).source_location } do
+    ruby_version_is ""..."3.4" do
+      it "includes core library methods defined in Ruby" do
+        file, line = Kernel.instance_method(:tap).source_location
+        file.should.start_with?('<internal:')
+
+        loc = nil
+        tap { loc = caller(1, 1)[0] }
+        loc.should =~ /\A<internal:.*in `tap'\z/
+      end
+    end
+
+    ruby_version_is "3.4"..."4.0" do
+      it "includes core library methods defined in Ruby" do
+        file, line = Kernel.instance_method(:tap).source_location
+        file.should.start_with?('<internal:')
+
+        loc = nil
+        tap { loc = caller(1, 1)[0] }
+        loc.should =~ /\A<internal:.*in 'Kernel#tap'\z/
+      end
+    end
+
+    ruby_version_is "4.0" do
+      it "does not include core library methods defined in Ruby" do
+        file, line = Kernel.instance_method(:tap).source_location
+        file.should.start_with?('<internal:')
+
+        loc = nil
+        tap { loc = caller(1, 1)[0] }
+        # CRuby hides the file which defines the method: https://bugs.ruby-lang.org/issues/20968
+        loc.should =~ /\A(<internal:|#{__FILE__}:).*in 'Kernel#tap'\z/
+      end
+    end
+  end
+end